Joe Tigay Buffett Bets on the AI Moat: Inside Berkshire’s Alphabet Buy
By Joe Tigay, Portfolio Analyst, Rational Equity Armor Fund
Warren Buffett, the world’s most famous value investor, just made one of his final major investment decisions before stepping down as CEO—and it was a direct, multibillion-dollar bet on the heart of the AI revolution. Following Friday’s filing disclosure, GOOGL shares surged 5-6%+ in Monday’s trading, and the market got a clear message: the Oracle of Omaha sees Google’s AI moat as not just defensible, but investable at scale.
The Portfolio Pivot: Decoding the Numbers
Berkshire’s Q3 2025 filing revealed a fascinating strategic shift: selling “old tech” gains to buy “future tech” value.
The Alphabet Bet: Berkshire purchased 17.85 million shares of Alphabet, valued at approximately $4.3 billion as of September 30, 2025. This instantly made Alphabet Berkshire’s tenth-largest U.S. stock holding.
The Apple Trim: Simultaneously, Berkshire reduced its Apple stake by roughly 15%, selling 41-42 million shares. Despite this reduction, Apple remains Berkshire’s largest holding at approximately $60.7 billion.
The Cash Position: Perhaps most telling, Berkshire’s cash reserves have swelled to a record $381.7 billion. This war chest underscores Buffett’s caution on overall market valuations, making this selective Alphabet purchase even more significant.
The Strategic Rationale: Moats, Regret, and Value
Buffett’s investment philosophy has always centered on businesses with wide, durable moats. By investing in Alphabet, Berkshire confirms that it views Google’s core businesses—Search, YouTube, and Google Cloud—as fortified, not threatened, by the AI revolution.
This move also rectifies what Buffett and the late Charlie Munger famously called a major regret. In 2019, they admitted they “blew it” by not buying Google earlier. Consider this the long-awaited correction.
From a valuation standpoint, Alphabet was the “cheapest” of the Magnificent Seven stocks in Q3, trading at a forward P/E of around 25x compared to peers like NVIDIA at 30x and Microsoft at 29x. For value investors, this represented a rare entry point into the AI sector at a reasonable multiple.
The Options Market Dimension: What Market Makers See
As a former options market maker in the SPX and VIX pits, I have to consider what Berkshire is likely doing beyond the equity purchase. With $381.7 billion in cash and a relatively small (by Berkshire standards) $4.3 billion stock position, there’s a high probability they’ve sold downside puts on Alphabet.
This isn’t speculation—it’s Berkshire’s playbook. Remember Coca-Cola? Buffett famously sold puts on KO in the early 1990s, essentially getting paid to wait for his price. From 2004-2008, Berkshire sold long-dated index puts, collecting $4.9 billion in float while betting on long-term market strength.
Here’s why this matters to every investor: when a player like Berkshire sells volatility—even on a single name like Google—it filters through the entire volatility space. This keeps downside protection cheaper than it would normally be, while simultaneously creating a built-in buyer if stocks do fall. For those of us managing portfolios at the Rational Equity Armor Fund, understanding these dynamics is critical. Berkshire’s put-selling essentially provides structural support to the market, making protective strategies more efficient.
What This Means for the AI Trade
Buffett’s investment sends three powerful signals to the market:
Immediate Validation: This gives the AI infrastructure boom a crucial vote of stability from the world’s most patient investor, countering concerns about excessive CapEx spending and valuation bubbles.
Capital Reallocation: It encourages conservative, long-term institutional capital to re-evaluate tech. If Buffett is buying, other disciplined allocators will follow, potentially driving multiple expansion for Alphabet.
Berkshire’s Evolution: As Warren prepares to hand leadership to Greg Abel, this technology bet signals that the next generation of Berkshire managers is willing to deploy capital into large-scale, high-quality companies dominating future technological trends.
Betting on the Durable Compounder
The Alphabet investment is more than a stock purchase—it’s a strategic endorsement of the company’s wide moat and a powerful vote that the AI infrastructure boom has years of runway ahead. Combined with Berkshire’s likely options strategy, it represents a masterclass in capital deployment: generating income through put sales, maintaining massive optionality with cash reserves, and securing equity upside in one of technology’s most durable franchises.
For investors tracking disciplined capital, the message is clear: look for high-quality businesses with strong moats that use technology to compound value over the long term. And as always, don’t just watch what the smart money buys—watch how they structure the bet.
Joe Tigay is a Portfolio Analyst for the Rational Equity Armor Fund and former options market maker in the SPX and VIX pits. When he’s not analyzing market structure, he’s a father of three amazing kids, eagerly watching what they’ll get up to next. Learn more about Joe’s background.
